Radar systems are known for transmitting and/or receiving radar signals in preferred directions using a transmission antenna and a separate receiver antenna or a single antenna that is used for both transmission and receipt. Phased array radar antennas include a multiple number of antenna elements that often are arranged in regular patterns and are connected to transmitter and/or receiver modules. For practical purposes, series of antenna elements and transceiver modules are often grouped into sub-arrays which are stacked to form a complete phased array. It is noted that in this context, both sub-arrays and array elements are denoted by tiles.
When a single transmitter tile and/or a single receiver tile does not operate properly, e.g. due to a defect, the resulting transmission antenna pattern and/or receiver antenna pattern deteriorates, thereby significantly increasing the radar system angular sensitivity to clutter and jammer signals. The performance of the radar system becomes worse thereby rendering a process of obtaining reliable radar observations more difficult.
In prior art systems, it is proposed to use only the largest part of the phased array that still operates. However, the radar system is then not used efficiently in terms of radar gain and power. Further, signals of failing elements can be estimated using data associated with neighbouring elements. Such a system is, however, not applicable when an entire sub-array fails. Alternatively, the defect transmitter tile or receiver tile can be replaced. However, this is time consuming and not always possible in an operational situation. The radar system is then temporarily unavailable.